A deadly new drug-resistant strain of the superbug MRSA could spread rapidly through the gay community, experts have warned.

The infection is already moving through parts of San Francisco in the same way as HIV and Aids did in the early 1980s. The bug, which can lead to a deadly flesh-eating form of pneumonia, is 13 times more prevalent among the city’s gay men than other people.

But researcher Dr Binh Diep said: ‘The potential widespread dissemination of the infection into the general population is alarming.’

The strain, a sub-type of the USA300 bug, is not caught in hospitals but spreads through a community, often by casual contact.

It causes tennis ball-size boils on the skin and, in severe cases, can lead to fatal blood poisoning or a necrotising pneumonia which devours the lungs.

There have been two cases of USA300 in Britain but Dr Diep’s study has shown that one in 588 men in one predominately gay community in San Francisco has the new strain.

As it is resistant to conventional antibiotics, it is difficult to treat.

MRSA expert Prof Mark Enright, from Imperial College and St Mary’s Hospital, London, said gay communities and drug users were particularly at risk. But it could also be spread by those involved in sports, such as wrestling, with skin-to-skin contact.

‘Having a number of sexual partners and making skin contact with a large number of different people is how these infections are picked up,’ he added.

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